1. Field of the Invention
The present invention pertains to the art of clothes washing machines and, more particularly, to a system for controlling a clothes washing machine which incorporates a heater.
2. Discussion of the Prior Art
In a typical clothes washing machine, the temperature of the washing liquid is basically established based on wash/rinse temperature selections made by the machine operator for a particular washing operation. Other factors, such as the temperatures of incoming water supplies and surrounding environmental conditions, can also have an affect on the temperature of the washing liquid. In order to counter these potential variations, it has been heretofore recognized that incorporating a heater in a washing machine can aid in establishing consistent washing liquid temperatures and, correspondingly, more uniform washing operations. Such prior art arrangements are exemplified by one or more of U.S. Pat. Nos. 3,750,429, 4,024,735, 4,580,421, 4,949,556, 5,038,586, 5,749,249, 5,832,553 and 6,044,510.
In general, these prior art arrangements concentrate on providing a heater in a washing machine for the sole purpose of establishing and/or maintaining a desired washing liquid temperature. However, the manner in which the heater is regulated during a wide range of control operations can have a significant impact on the consistency, effectiveness and efficiency of various washing operations. With this in mind, there exists a need in the art for a control system for a washing machine which regulates the activation and de-activation of an incorporated heater during specified cycles and cycle times, as well as enables a pre-established cycle operation to be altered based on heater related parameters, in order to enhance the washing characteristics of the machine.
The present invention is directed to a clothes washing machine incorporating a heater, wherein the washing machine includes a control system that regulates both the heater based on selected cycle operations and selected cycle operations based on heater related parameters. At a base level, the heater, which is preferably positioned in a sump area defined by an outer tub of the washing machine, is adapted to be energized when the washing liquid temperature falls below a target temperature by a pre-establish temperature fluctuation value, e.g., 5xc2x0 F., during a main washing cycle. On other levels, the heater is controlled so as to be de-activated during predetermined cycle operations, particularly pre-soaking and bleach fill operations. On still other levels, the actual temperature established by the heater is sensed and, if the washing liquid temperature is less than desired during a certain operating cycle, the operation of the cycle itself is modified. For instance, the washing machine of the present invention preferably incorporates a stain cycle option during which the heater is activated. If the temperature of the washing liquid is less than a predetermined temperature, e.g., 95xc2x0 F., additional time is added to a portion of the stain cycle in order to enhance the stain removal sequence.
Additional objects, features and advantages of the present invention will become more readily apparent from the following detailed description of a preferred embodiment when taken in conjunction with the drawing wherein like reference numerals referring to corresponding parts in the several views.